This invention relates to the synthesis of aromatic-imide and aromatic-methylidynetrissulfonyl species. The synthesis proceeds by reaction of aromatic species, including aromatic polymers, with a reactant according to the formula: (Xxe2x80x94SO2xe2x80x94)mxe2x80x94QHxe2x80x94(xe2x80x94SO2xe2x80x94R1)n; wherein Q is C or N and X is a halogen. The present invention additionally relates to compounds according to the formula: (Arxe2x80x94SO2xe2x80x94)mxe2x80x94QHxe2x80x94(xe2x80x94SO2xe2x80x94R1)n wherein R1 comprises a highly acidic group selected from sulfonic acid, carboxylic acid and phosphonic acid, which may be particularly useful as electrolytes.
U.S. Pat. No. 6,090,895 discloses crosslinked polymers having imide crosslinking groups and methods of crosslinking polymers to form imide crosslinking groups. These crosslinked polymers may be useful as polymer electrolyte membranes (PEM""s) in fuel cells. The reference discloses methods of making imides by reaction of acid halides with amides, including aromatic acid halides and aromatic amides. The acid halides may be formed by haloacidification, e.g., chlorosulfonation, of aromatic species.
U.S. Pat. No. 6,063,522 discloses electrolytes for use in electrochemical cells that include imide and methide conductive salts. The reference also discloses methods of making imides by reaction of acid halides with amides.
U.S. Pat. No. 4,505,997 discloses syntheses of imides by reaction of sulfonate and sulfonic anhydride species with urea. The reference discloses electrolytes comprising imide functional groups.
U.S. Pat. No. 5,652,072 discloses syntheses of imides by reaction of sulfonyl halide species with ammonia or with amide species. The reference discloses electrolytes comprising imide functional groups.
U.S. Pat. No. 5,072,040 discloses syntheses of imides by reaction of sulfonyl halide species with nitride species. The reference suggests the use of imide functional species in electrolytes.
U.S. Pat. No. 5,514,493 discloses syntheses of imides by reaction of sulfonyl halide species with ammonia or with amide species. The reference discloses electrolytes comprising imide functional groups.
U.S. Pat. No. 5,463,005 discloses perfluorinated monomers and polymers comprising sulfonyl and carbonyl imide groups for use as solid polymer electolytes. The reference discloses a synthesis of imides by reaction of amides with hexamethyldisilazine followed by reaction with a sulfonyl fluoride.
Argyropoulos and Lenk, xe2x80x9cCondensation Products from Imidobis(sulfuryl Chloride),xe2x80x9d J. Ap. Polym. Sci. v. 26, pp. 3073-3084 (1981), discloses reactions of imidobis(sulfuryl chloride).
Briefly, the present invention provides a method of making aromatic-imide and aromatic-methylidynetrissulfonyl species by reaction of aromatic species with a reactant according to formula (I):
(Xxe2x80x94SO2xe2x80x94)mxe2x80x94QHxe2x80x94(xe2x80x94SO2xe2x80x94R1)nxe2x80x83xe2x80x83(I)
wherein Q is C or N; wherein each X is independently selected from the group consisting of halogens, typically F or Cl; wherein each R1 is independently selected from the group consisting of aliphatic and aromatic groups, which may or may not be saturated, unsaturated, straight-chain, branched, cyclic, heteroatomic, polymeric, halogenated, fluorinated or substituted; wherein m is greater than 0; wherein m+n=2 when Q is N; and wherein m+n=3 when Q is C. Ar may be derived from an aromatic polymeric compound.
In another aspect, the present invention concerns compounds according to formula (V), which compounds may be made using the method according to the present invention:
(Arxe2x80x94SO2xe2x80x94)mxe2x80x94QHxe2x80x94(xe2x80x94SO2xe2x80x94R1)nxe2x80x83xe2x80x83(V)
wherein Ar is an aromatic group derived from an aromatic compound; wherein Q is C or N; wherein each R1 is independently selected from the group consisting of aliphatic and aromatic groups, which may or may not be saturated, unsaturated, straight-chain, branched, cyclic, heteroatomic, polymeric, halogenated, fluorinated or substituted; wherein at least one R1 contains at least one highly acidic group selected from sulfonic acid, carboxylic acid and phosphonic acid; wherein m and N are each greater than 0; wherein m+n=2 when Q is N; and wherein m+n=3 when Q is C.
What has not been described in the art, and is provided by the present invention, is a simple method of synthesizing aromatic imides and aromatic methylidynetrissulfonyl species by direct substitution of aromatic species, including pre-existing aromatic polymers, by use of the reactants described herein.
In this application:
xe2x80x9chighly acidicxe2x80x9d means having a pKa less than 5;
xe2x80x9chighly halogenatedxe2x80x9d means containing halogen in an amount of 40 wt % or more, but typically 50 wt % or more, and more typically 60 wt % or more; and
xe2x80x9chighly fluorinatedxe2x80x9d means containing fluorine in an amount of 40 wt % or more, but typically 50 wt % or more, and more typically 60 wt % or more; and
xe2x80x9csubstitutedxe2x80x9d means, for a chemical species, substituted by conventional substituents which do not interfere with the desired product or process, e.g., substituents can be alkyl, alkoxy, aryl, phenyl, halo (F, Cl, Br, I), cyano, nitro, etc.
It is an advantage of the present invention to provide a simple and convenient synthetic route to aromatic-imide and aromatic-methylidynetrissulfonyl electrolytes, including solid polymer electrolytes, which are useful in electrochemical devices such as batteries and fuel cells.
The present invention provides a method of making aromatic-imide and aromatic-methylidynetrissulfonyl species by reaction of aromatic species with a reactant according to formula (I):
(Xxe2x80x94SO2xe2x80x94)mxe2x80x94QHxe2x80x94(xe2x80x94SO2xe2x80x94R1)nxe2x80x83xe2x80x83(I)
wherein Q is C or N; wherein each X is independently selected from the group consisting of halogens; wherein each R1 is independently selected from the group consisting of wherein R1 is selected from the group consisting of aliphatic and aromatic groups, which may or may not be saturated, unsaturated, straight-chain, branched, cyclic, heteroatomic, polymeric, halogenated, fluorinated or substituted; wherein m is greater than 0; wherein m+n=2 when Q is N; and wherein m+n=3 when Q is C.
For the reactant according to formula (I), Q may be C or N but is more typically N. Where Q is N, m may be 1 or 2. Where Q is C, m may be 1, 2 or 3, but is typically 1 or 2. Each X is a halogen, typically F or Cl, and most typically Cl.
R1 is any suitable group that does not interfere with the synthesis according to the present invention and which provides a product having desired characteristics. Each R1 may be aromatic or aliphatic; may be saturated or unsaturated; may be straight-chain, branched, or cyclic; may be heteroatomic or non-heteroatomic; may comprise a polymer; and may additionally be substituted including in particular halogenation, including in particular fluorination. R1 typically comprises between 0 and 20 carbon atoms, more typically 0 to 8 carbon atoms, more typically 0 to 4 carbon atoms. Where the product species is intended for use as an electrolyte, R1 is typically highly halogenated, more typically highly fluorinated, more typically perhalogenated, and most typically perfluorinated. Where the product species is intended for use as an electrolyte, R1 is typically selected from: trihalomethyl, pentahaloethyl, heptahalopropyl, and nonahalobutyl, more typically where halogen substituents are selected from F and Cl. More typically, R1 is selected from: trifluoromethyl, pentafluoroethyl, heptafluoropropyl, and nonafluorobutyl, most typically trifluoromethyl.
R1 may advantageously contain additional highly acidic groups, typically including sulfonic acids, carboxylic acids and phosphonic acids, most typically sulfonic acid groups. R1 may contain the highly acidic group according to formula (IV): 
wherein Q and X are as defined above, wherein R1, is selected from the same group as R1 defined above except that R1, is typically not another group according to formula (IV), wherein p+q=1 when Q is N; and wherein p+q=2 when Q is C.
Alternately, R1 may advantageously contain additional aromatic-binding groups such as sulfonyl halides or groups according to formula (IV) above where p greater than 0. Where R1 contains additional aromatic-binding groups and Ar is polymeric, crosslinking may result.
The reactant according to formula (I) above may be synthesized by methods such as described in Roesty and Giere, xe2x80x9cDarstellung von N-Trifluormethanesulfonyl-sulfonylfluoridamid und einige reaktionen,xe2x80x9d Inorg. Nucl. Chem. v. 7, pp. 171-175 (1971) or Becke-Goehring and Fluck, xe2x80x9cImidodisulfuric acid chloride,xe2x80x9d Inorganic Synthesis, v. 8, pp. 105-107 (1966)), which are incorporated by reference herein, or by methods analogous thereto, or by other methods known in the art.
Ar may be polymeric or non-polymeric. Polymeric examples of Ar include polymers with aromatic groups in the polymer backbone, such as polyphenylene oxide (PPO), and polymers with pendent aromatic groups, such as polystyrene. Aromatic polymers which may be useful as Ar in the present reaction include PPO, polystyrene, polyether ether ketone (PEEK), polyether ketone (PEK) and polysulfone and substituted derivatives thereof. Where m is greater than 1, a crosslinked product may result. Mixtures of reactants may be used to control the degree of crosslinking, such as mixtures of m=1 reactants and m=2 reactants.
Non-polymeric examples of Ar include aromatic groups having 5 to 20 carbon atoms, including monocyclic and polycyclic species and including heteroatomic and non-heteroatomic species. Additional aromatic species which may be useful as Ar in the present reaction include: benzene, toluene, naphthalene, anthracene, phenanthrene, fluorene, biphenyl, terphenyl, stilibene, indene, chrysene, pyrene, tetracene, fluoranthrene, coronene, pyridine, pyridazine, pyrimidine, pyrazine, imidazole, pyrazole thiazole, oxazole, triazole, quinoline, benzofuran, indole, benzothiophene, carbazole, and aromatic isomers and substituted derivatives thereof.
The aromatic reactant and the reactant according to formula (I) may be combined under any suitable reaction conditions. The reaction conditions are advantageously anhydrous. The reactants may be combined in solvent or neat. Where Ar is polymeric, the reactants are typically combined in an inert solvent such as CCl4. Alternately, the reactant may be imbibed into the polymer, either neat or by use of a solvent. In this case, the polymer may be preformed into a membrane or other useful shape. The reaction mixture is typically heated. Catalyst may be added but is not necessary.
The method of the present invention may be used to make a class of aromatic-imide and aromatic-methylidynetrissulfonyl species bearing additional acidic functions which may be useful as electrolytes, according to formula (V):
(Arxe2x80x94SO2xe2x80x94)mxe2x80x94QHxe2x80x94(xe2x80x94SO2xe2x80x94R1)nxe2x80x83xe2x80x83(V)
wherein Ar is an aromatic group derived from an aromatic compound; wherein Q is C or N; wherein each R1 is independently selected from the group consisting of aliphatic and aromatic groups, which may or may not be saturated, unsaturated, straight-chain, branched, cyclic, heteroatomic, polymeric, halogenated, fluorinated or substituted; wherein at least one R1 contains at least one additional highly acidic group; wherein m is greater than 0; wherein n is greater than 0; wherein m+n=2 when Q is N; and wherein m+n=3 when Q is C. Typically, Q is N, m=1 and n=1. Typically, the additional acid group of R1 is selected from sulfonic acids, carboxylic acids, phosphonic acids, imides, and methylidynetrissulfonyl groups, most typically sulfonic acid groups. R1 may advantageously comprise an aromatic group. R1 may advantageously comprise an aromatic group according to the formula: xe2x80x94PhY5-v(SO2H)v where Ph is phenyl; each Y is independently selected from H, F, Cl and CH3; and v is 1, 2 or 3, more typically 1 or 2, most typically 1.
Compounds according to formula (V) include those wherein Ar is derived from an aromatic polymeric compound. In one embodiment, Ar is an aromatic polymer bearing numerous pendent imide or methylidynetrissulfonyl groups according to formula (V). Suitable polymers may include polymers with aromatic groups in the polymer backbone, such as polyphenylene oxide (PPO), and polymers with pendent aromatic groups, such as polystyrene. Aromatic polymers which may be useful as Ar in the present reaction include PPO, polystyrene, polyether ether ketone (PEEK), polyether ketone (PEK) and polysulfone and substituted derivatives thereof.
This invention is useful in the synthesis of aromatic-imide and aromatic-methylidynetrissulfonyl electrolytes, including solid polymer electrolytes, which are useful in electrochemical devices such as batteries and fuel cells.